Topic: Throttle spring causing wrist injury, too much return spring force?

[dboblet]

Oh, My Aching Wrist.  I can't see doing a long trip with this much return spring tension.  Evey a half hour commute leaves my wrist aching and is beginning to build callouses on my palm.

So. what to do??
The cables are fine, easy free movement, it's not overcoming cable play that's the problem, it's dealing with extremely strong return spring tension.  Is there a simple fix, or do I have to pull the carbs and play with the spring itself? (which is what I suspect I'll have to end up doing).
And while I'm ranting... Do I really need a return cable?  I can't see the benifit of a push cable when the return spring tension is this strong.

[Deltarider]

Do I really need a return cable?  I can't see the benifit of a push cable when the return spring tension is this strong.

That return cable is just one of the silly safetymeasures American authorities demanded. There are quite a few (Objects in this mirror may... etc). Killswitch. Not to mention demands in the environmental field. I've run my bike almost 15 years without that returncable. Never dared to stretch that main spring though. I hate the b.....d too.

[shoemanII]

i unwound the throttle return spring hook about 1/2 to 3/4turn.  one end now rests against the carb rack flat bar.  hard to explain, easy when you look at it.  hook is secured w/little tywrap, throttle is so easy now, feels like an FI bike.  did this on my '78k and '78k engine-equipped '78f.         

[dboblet]

I haven't looked yet, but does this mean you are relying on a plastic zip-tie to secure your return spring?  Sounds kind of iffy to me.  But I may just try it.  As for the return cable, I'm about 3/4 convinced I should take it off...  The push cable on my bike is old (original so 30 years old) and the pull cable is a brand new honda replacement.

Hey, does this mean that european bikes do not have a push cable?

[eurban]

If you weaken your throttle return spring, do yourself a favor and keep the return cable.  Combining these two mods is truly asking for trouble . . .  .

[TwoTired]

I haven't looked yet, but does this mean you are relying on a plastic zip-tie to secure your return spring?  Sounds kind of iffy to me.  But I may just try it.  As for the return cable, I'm about 3/4 convinced I should take it off...  The push cable on my bike is old (original so 30 years old) and the pull cable is a brand new honda replacement.

Hey, does this mean that european bikes do not have a push cable?

Honda early 750 carbs had a return spring in each carb (4 of them) and a single pull cable to open them against the springs.  The springs were captive and even a spring broke, the other three carbs would close normally and one would close sluggishly.  Not much of a safety issue.

The newer style carbs have a single return spring, if that breaks from metal fatigue after thirty years of tension/flexing, then the only thing to positively close the throttle is the "push" cable.  If the circumstances are right, you could hit the kill switch, pull the clutch and let the engine race to destruction, etc., in order to keep from accelerating wildly.  However, if it were my bike, the spring would break as I was approaching a mountain curve with a steep cliff drop off, or an oncoming truck in the outside lane.  The unnatural act of hitting the kill switch would occur to me just prior to impact.

Good luck on you choice!

[PJ]

I had the same problem, I went to the auto parts store and bought a collection of carb springs and I managed to find one soft enough to be *ok*. If I release the throttle it doesn't snap closed but it does close. Sometimes it needs a nudge to close back to idle. I wouldn't remove the push cable especially if you go with a light spring, it should only have slight resistance anyway. If it's more then I would replace it. Trying to be smarter than the guys that engineered it could leave you on the side of the road or worse.. the side of a truck..

[Dunk]

I concur on the return spring pressure. Since I put new bars on my bike a couple weeks ago and cleaned up the throttle plastic that twists on teh bars, it snaps closed with vigor. I think all the nasty gunk and grease in the throttle tube dampened the spring enough to be comfortable. I rode out to Carlisle without gloves and it hurt my hand like mad, calloused up and raw from holding the grip. Kept having to adjust my grip since it would slip closed if I sweated at all. With gloves it's not as bad, but still painful for a long ride.

I think a slightly weaker spring would solve the problem. I'll keep the return cable on my bike though as if the spring ever fails I have no way to quickly and easily close the throttle. Just a matter of how quickly I hit the kill switch. If my hand is already on the throttle then that's faster and easier to twist closed than going for the kill switch.

[mystic_1]

The cables are fine, easy free movement, it's not overcoming cable play that's the problem, it's dealing with extremely strong return spring tension.  Is there a simple fix, or do I have to pull the carbs and play with the spring itself? (which is what I suspect I'll have to end up doing).

Adjust the throttle tensioner, if so equipped.  It's on the underside of the right control pod.

See the following post:

http://forums.sohc4.net/index.php?topic=36815.0

If your bike does not have one, a weaker throttle spring is your only option, unless you retrofit a tensioner.

mystic_1

[lone*X]

One other option is the "Throttle Rocker", an inexpensive add on to the throttle grip that gives you a palm rest at the end of the grip.  I used one for a couple of years before adding a cruise control to my VTX.  It really allows you to relax your hold on the grip while maintaining the throttle position.  Saved a bunch of tight forearm and neck muscles in my case.

[eldar]

I think you all just suffer from "yankers" wrist! 
you all need a support group so you can come to terms with too much yanking!!



 

[CB750F2]

G'Day from Nth Queensland. I use the gadget described by Don in the previous post. This device clamps onto the throttle grip and provides a saddle or seat for the heal of the right hand. It allows you to release the fingers on the throttle when tired and still maintain throttle position with the heal of your hand. In my case I have drilled a hole large enough for a cable tie and I use the cable tie to increase the clamping force of the device onto the throttle grip. If this is not done the device will gradually slip out of position. I have two F2s but only one has this device fitted and because of this it is much more comfortable on a long ride. I also find that I change gears quicker and smoother with this device. Pat

[shoemanII]

re: the zip tie

my slightly "unwound" return spring causes the throttle to nearly close when released.  i sometimes need to fully bring it to idle manually. i zip tie everything and just mentioned it: the spring end is held there by tension.
bobp

[fuzzybutt]

my right wrist is good and strong, i excercise it plenty 

[jjwaller]

No, No:

On the 77, 78's the throttle spring is ridiculous.
What I've found is to unwrap the spring (roughly),
3/4? of a turn and hook the spring on the tiebar instead of the
carb body as it is supposed to go.  If you hook it over the bar
it won't come off.  It looks at first that it might come off, but it
wont.  Worked for 30 years, no problems.
And yes, make sure that your cables are absolutely free.
Makes a BIG difference.
HTH

[dboblet]

Thanks for all the input.  I've decided to leave the push cable for safety   
I've also decided to monkey with the return spring and unwind it a bit.  It's so strong now that without the cables attached I 'almost' can't open it by hand.  I 'popped' a blister on my hand this morning trying to hold the throttle open on the way to work.  Interestingly, it's harder to hold onto while wearing gloves and I seldom ride without gloves.  I think I'll start a new thread on gloves next, if there isn't one. 
Anyway, I'll try to takes some revealing before and after pics of the throttle spring, just for fun.

[eldar]

It is not unusual to have more difficulty yanking with gloves on. gloves can slip a little making you have to grip things harder!
 

Seriously, the glove does slide a small bit and then requires more hand strength to hold the throttle.

[Markcb750]

Lube & or replace the cables, the Motion Pro units are nice!

Beyond that…I would suggest seeing a surgeon who specializes in Carpal tunnel  corrections who will gleefully schedule you for corrective surgery.

You will experience some of the most interesting pain a human can, your hand will be immobilized for weeks, you will have interesting scars.

He will then write you a prescription for physical therapy, this will be OK if the therapist is young, attractive, and of the sex you prefer.

Or


You could start some hand and wrist exercise, I suggest the old fashion torsion spring units, in the color of your choosing.


Some times simply changing the angle can help, many professional typists (like my wife) have learned to alter the height & distance of their keyboard.

[mystic_1]

Thanks for all the input.  I've decided to leave the push cable for safety   
I've also decided to monkey with the return spring and unwind it a bit.  It's so strong now that without the cables attached I 'almost' can't open it by hand.  I 'popped' a blister on my hand this morning trying to hold the throttle open on the way to work.  Interestingly, it's harder to hold onto while wearing gloves and I seldom ride without gloves.  I think I'll start a new thread on gloves next, if there isn't one. 
Anyway, I'll try to takes some revealing before and after pics of the throttle spring, just for fun.

At first I think I read this wrong, I got the image of you riding the bike around with NO throttle cables, by working the carb slides with one hand and steering with the other.  I was thinking that was pretty hardcore, brother lol!  Then I realized my mistake.

As far as gloves go, what sort of grips are you using?  What are the gloves made of?  Makes a difference.  Leather gloves on robber grips, for exampe, is good.  Leather gloves on metal grips, usually ok.  Leather gloves on foam grips, not so good.

BTW I see from your previous posts that you're driving a 78F, no throttle friction lock on those, sorry.  My K0 has one, years ago when I first got the bike, I installed a NOS spring and immediately had problems like you described.  Research showed I was missing the adjuster screw and spring from the tensioner, installed those and throttle works like a champ.  Once I've twisted it to a particular position, the throttle tends to stay there with little effort, but if I let go the throttles snap closed nicely.  No more cramps on cross country rides.

Items 13, 15, and 16 below are what I'm talking about:



But it looks like these were only on K0 through K2 750's and a few of the smaller bikes.

Of course, I also later installed one of these, for even lazier driving pleasure



The combination of both works quite well, been using this setup for years now.  A throttle lock won't help much in round-town driving unless you leave it engaged all the time, but it will wear out quicker this way.  All of these things work by providing friction against the throttle tube or grip.

mystic_1

[gar]

I bought a cheap plastic 'throttle rocker' from denniskirk.com... I think it cost about $10... it has never come off my 550 since I put it on a year ago.  It makes riding far more pleasurable, because my bike too has an excessive return force on throttle. Seriously--buy one and your problem will be solved.

[Ichiban 4]

With a '77 550..I experienced the same thing with what I felt to be..excessive throttle spring tension.  I have never before experienced throttle resistance..where one had to actively "hold the throttle open"..to keep it from shutting down automatically.

Well..yes..the throttle should shut down to an idle on it's own..when one's hand isn't actually on the grip. But I've never before the '77..experienced the need to actively "hold the throttle open" with exertion before.  Just the weight of one's hand-wrist has usually been sufficient to hold the throttle open with most other (road/street) bikes I've ridden.

So..to make a long story short here..I did what PJ earlier said: went down to the local hardware store..compared springs to what came-off originally....and selected one that was slightly lighter in tension than the stock item.  Bottom line: the throttle is much easier to use/ride with for longer periods of time.  Caveat: to get the bike to idle down completely (say from 1500>>1200 RPM) one has to manually "close the throttle all the way".  The comments about having properly lubed cables..is also important..I've found.

Ichi

[quietlikeachurch]

'77/'78 carbs are almost maliciously oversprung.  Heavy throttle seems to be a design fault in any post-4-spring 750.  I just yesterday had the pleasure of monkeying around with a '69 750 and the throttle was absurdly soft...like a tub of "lite" margarine vs a cold stick of butter.  I would give a pinky finger for a set of 1st gen. carbs despite the syncing headaches...

[Bido]

I put a wrist rocker on my 78f and have no problem.  Cowboy Up !!!!

[WFO]

I deal with the same thing on my 82 iam glad you started this thread.

[dboblet]

"Cowboy up" my posterior orifice!!  I want a bike that won't kill my wrist.  I've got the death grip and if I have to grab the brake lever fast, my fingers are so tightly wound on the handle that they would never make it to the brake lever to do any good.  I'll pull the carbs on Tuesday and takes some pics of what I end up doing.